March 29, 1993: Teleportation Beams From Sci-Fi to Real Science

1993: Scientists show teleportation is possible, at least theoretically. The downsides: The original teleported object must be destroyed, and it can’t happen instantaneously.

In a paper published in the scientific journal Physical Review Letters, researchers showed information about a quantum state can be transported via teleportation, which they define as “a term from science fiction meaning to make a person or object disappear while an exact replica appears somewhere else.” The sender, whom they dub Alice, doesn’t even need to know anything about the quantum state to teleport its information to Bob, the receiver.

Say Alice has a quantum system, and she wants to send its 411 to Bob so he can make an exact replica. But she doesn’t know much about her quantum system, so she has a conundrum on her quantum system-bearing hands. If she tries to measure its properties, like its location or momentum, she’ll invariably disrupt it. And if she disrupts it, she can’t send Bob information accurate enough for him to make a carbon copy. So, how does she get out of the catch-22?

That’s where entanglement — when two or more intertwined particles share physical properties across space and maybe time — comes to the rescue. Measuring the properties of one entangled particle will change its twin’s characteristics. Einstein referred to entanglement as “spooky action at a distance.”

Alice can make her quantum system interact with an entangled system — let’s call it Carrie — whose properties she does know. She has one Carrie particle, and Bob has its twin. When her Carrie particle interacts with her unknown quantum system, information about her mystery system is transferred over to Carrie. Because her Carrie twin is entangled with Bob’s, he now has access to that information and he can use it to reconstruct Alice’s unknown particle. Alice’s original is, of course, destroyed in the process.

And that’s likely a good thing. According to IBM’s quantum teleportation website: “A few science fiction writers consider teleporters that preserve the original, and the plot gets complicated when the original and teleported versions of the same person meet; but the more common kind of teleporter destroys the original, functioning as a super transportation device, not as a perfect replicator of souls and bodies.”

Since the original teleportation paper was published on this day in 1993, other teams have shown teleportation, also popularly known as “beaming up,” is more than just theoretically possible. In 1998, Caltech scientists teleported a photon about three feet. Another group was able to teleport quantum information over a distance of more than 10 miles.